The diaphragm is a soft latex rubber cup that should
be used with spermicidal jelly or cream. The diaphragm is a
shallow, dome-shaped cup with a flexible rim that fits securely
in the vagina to cover the cervix. The diaphragm blocks a man’s
semen from entering the cervix (the opening to the womb). A
spermicide placed onto the diaphragm kills sperm. Diaphragm
and the spermicide keep sperm from getting to the egg.